1. Field of the Invention
The present invention relates to an EPDM composition and an automotive brake system rubber component made of the EPDM composition.
2. Related Art
Ethylene-propylene rubber (EPM) or ethylene-propylene-non-conjugated diene rubber (EPDM) is widely used for automotive brake system components such as brake system hoses and seal components.
In the case of EPDM, a sulfur curing system EPDM is used and it is normal that a vulcanization accelerator and zinc while, which functions as a vulcanization accelerator assistant, are mixed into the EPDM.
Incidentally, a brake system hose is mounted to be connected to a metallic pipe to which copper plating is applied. On the other hand, part of the vulcanization accelerator is eluted into a brake fluid depending upon the type and amount of the vulcanization accelerator into which rubber is compounded. A substance eluted from the vulcanization accelerator reacts with the copper plating, and then, the copper plating is stripped from the metallic pipe or a reaction product resulting from the reaction between the eluted substance and the copper plating settles in the brake fluid.
Due to this, it is considered to use peroxide curing system EPM compositions and EPDM compositions which contain no vulcanization accelerator. In consideration of the adhesive property thereof to fabric making up a reinforcement layer and the durability thereof which is one of product performances, however, those peroxide curing system EPM and EPDM compositions are not suitable for brake system hoses.
In addition, the elution of rubber compound is also found in a radiator hose which is made of a sulfur curing system EPDM composition, and this is coped with by dealing properly with types and amounts of vulcanization accelerators that are to be compounded (refer to JP-A-2001-106848). However, even when the EPDM composition has been applied to brake system hoses, no sufficient effectiveness has been obtained yet.